# Coordinates calculation using QGIS

I am quite new to GIS software. I use QGIS. I have a question that might be trivial. I would like to derive the coordinates (Y and X) for an area. Just to make an example: I have two regions A and B. From the shapefile I know which are their coordinates. However, I would need the coordinates for the unique region A+B. Could you please give me some hints on how to do that?

• What do you mean by "coordinates for an area"? An area does not have coordinates, a point does. – ArMoraer Apr 20 '16 at 16:24
• Yes you are right. I mean lon and lat for the points determining the region (A+B). It seems to me that field calculator should be used, but I am a bit lost with it. – Dario Apr 20 '16 at 16:43
• What do you mean by region A+B? Depending on what you mean that, you could do something like a merge or intersection, then extract the coordinates of the vertices. Just make sure that the geoprocessing step that you use is consistent with what you mean by A+B. – Ezra Boyd Apr 20 '16 at 22:40
• Thanks for your reply. What I mean is the following. Example: In the original shape file I have information about the coordinates to plot Spain an Portugal. I need to plot them as a single area. Therefore, I need the coordinates to plot spain+Portugal as they were only one country. So if I understood correctly, you suggest to merge them and to extract the coordinates of the vertices. This should work for my case. I presume that I can merge them highlighting those two countries on the map. But then how can I extract the coordinates of the vertices? – Dario Apr 21 '16 at 1:14

• Union still has the border in the middle. Dissolve using `Dissolve all` creates one polygon covering all elements. – AndreJ Apr 21 '16 at 5:38